There exist many computer programs today that assist a user in editing data on a computer. For example, a word processing program enables a user to enter and modify textual data. A computer-aided drafting program enables a user to enter and modify graphical data. A digital signal-editing program enables a user to load digital signal data, modify the digital signal data, and save the digital signal data. Such a digital signal may represent audio data, for example.
For example, some computer programs allow a user to edit audio signal data. The audio signal data represents sound, such as sound that was recorded using a microphone. In order to illustrate aspects of the audio signal data to a user, such computer programs typically display a visual representation of the audio signal data. For example, a computer program may display a two-dimensional waveform that depicts the variation of the amplitude of the audio signal data's represented sound over time.
A user might want to edit audio signal data for various reasons. For example, the user might want to apply effects such as echo to the audio signal data's represented sound, or the user might want to cut out a selected time portion of the audio signal data. Sometimes, a recorded sound may contain undesirable elements that the user would like to eliminate from the audio signal data. For example, a recording of music at a live concert might contain background sounds such as coughing and sneezing. When the user really just wants a clear recording of the music, the user would rather eliminate the coughing and sneezing that is heard in the background.
Eliminating such undesirable elements can be challenging. Merely cutting out the time portions of the audio signal data that contain the undesirable elements is over-inclusive because the cutting also eliminates sound that the user want to retain in the audio signal data. Using a two-dimensional amplitude-over-time display as discussed above, a user might try to adjust aspects of the audio signal data in order to remove only the undesirable elements. However, a two-dimensional amplitude-over-time display often does not provide a user with the ability to alter audio signal data in a precise manner. Too often, the only adjustments that the user can make using such a display are relatively coarse, inexact, and approximate. The two-dimensional amplitude-over-time display does not provide the user with the detailed information that he needs in order to perform “surgical” operations to excise undesirable sounds while leaving the remainder of the audio signal data intact and faithful to the source sound.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.